Photographic-printing process



UNITED STATES PATENT OFFICE.

JOHN EDWARD THORNTON, OF WEST HAMPSTEAJ), LONDON, ENGLAND, ASSIGNOR TO JOHN OWDEN OBRIEN, 0F MANCHESTER, ENGLAND.

PHO-TOGEAPHIC-PRINTING PROCESS.

Specification of Letters Patent. Patented Feb. 28, 1922.

No Drawing. Original application filed March 21, 1916, Serial No. 85,702. Divided and this application filed July 8, 1919. Serial No. 309,428.

To all whom it may concern Be it known that I, JOHN EDWARD THoRN; TON, a British subject, residing at West Hampstead, London, England, have invented certain new and useful Improvements in and Relating to Photographic- Printing Processes, of which the following is a specification.

This invention relates to the production of kinematograph films.

The object of the invention is to preparea printing belt or belts by which transparent kinematograph films of continuous length can be produced by mechanical printing of the pictures thereon With applied inks or colours, as distinct front printing photographically with sensitive chemical media acted upon by light, and as distinct from applying colour to a photographically printed series of ictures.

The original picture film of continuous indefinite length is photographed in the ordinary way, and from this the one or more printing belts are prepared by one of the processes known in photo-mechanical printing as reversed collotype, reversed hydrotype or reversed pinatype in which the fine dots, lines or other screen markings consist of a spongy porous absorbent medium, into which an aqueous or spirituousink or colour is absorbed and from which it can-be subsequently transferred to the surface of the transparent kinematograph film of continuous length by the pressure of the printing belt thereon.

Photo-mechanical printing is defined as follows :The actual operation of printing requires neither the use of a sensitive sur-' face nor'the action of light, nor subsequent development. Instead of such methods printing is effected by mechanical pressure of the film against a plate (in the form of a continuous belt) which has been prepared with a series of images by one of the photomechanical processes. a

The medium used to form the imagev is therefore a printing orapplied ink or colour of aqueous or spirituous character instead of .a sensitive salt. Various kinds of inks or colours can be used according to the particular type of engraved or other printing plate (herein termed printing belt) used.

I prepare a strip or band of copper, steel, brass, aluminium or other metal, or a strip of gelatine, the gelatine being on a supporting base, or a strip of celluloid with a coating of gelatine or other colloid, prepared with a sensative surface in any of the methods Well known for photo-mechanical printing to re- .pieive an lmpression of the original picture lm.

The prepared strip which is to form the printing belt is'perforated or notched along its margins or centre to correspond precisely with the perforationsor notches in the cam- .era film and. in the transparent kinematogra h film of continuous indefinite length.

pon the prepared strip I prepare a mechanical printing surface (hereinafter referred'to as a printingbelt) comprising a surface having a spongy porous character divided into a number of broken tone mark ings of fine dots, lines or other screen markings which will absorbwatery 0r spirituous ink, and interspersed with hardened parts which will not absorb the ink.

The gradations of light and shade are produced by varying the areas of the spongy or absorbent dots or lines.

In preparing printing belts from the original picture film, more particularly of the individual elemental colours, two or more of such printing belts may be made from each, one lightly exposed for the dense parts and the other fully exposed for the lighter tones.

By printing from one or other of these printing belts, or from both in succession, a high degree of tint is reached and desirable or The printing belt is made of a strip of indefinite length of metal, celluloid or other material, and for the hydrotype process it is made with a bichromated gelatine image in relief, prepared by exposure to light under a negative through the celluloid backing and then developed .with hot water from the front, thus yielding an image in varying degrees of relief. This is then soaked in watery or spirituous ink (a solution of 'dye) which is then transferred to the film by pressure maintained for a long enough period to transfer suflicient dye.

By a variation of this hydrotype principle, known as pinatype, the bichromate image is not developed into relief after exposure, but after washing out the surplus -biohromate the soft parts of the gelatine are dyed up instead of the hardened parts, the dye being next transferred by pressure as before. In still another variation of this principle, known as the Donnisthorpe process, the hardened parts of the image are dyed.

A process for forming a printin surface of actual hardened gelatine is the eimtype of Husnik which is briefly described on ages 330 and 331 of Cassels Cyclopaedia of hotography published in 1912, and further a description is given in Husniks British Specification No. 37 of 1887. To obtain the most satisfactory results by the Leimtype process certain improvements and modifications are desirable, and these, as hereinafter described, must be regarded as a part of the present invention. The film base is a flexible band of metal, celluloid or other material grooved or perforated to promote the adhesion of the gelatine with which it is coated, this coating being on one side or both, and the gelatine having been sensitized and plrmted and treated in accordance with the usnik method gives a grained typographic surface.

The printing belt may be prepared by the reversed collotype process known as hydrotype or pinatype. This method allows of a certain amount of diffusion of the colour in the gelatine layer but does not yield ex tremely sharp images, and is .therefore better" suited for thered image and the yellow image for printing over a direct cyanotype or other dlrect sharp photographic image than for all the three stages of a colour film. For this form of hydrotype a grained or cross hatched or grooved cellulold band is desirable, the slight grain resultin therefrom tending to merge into a tone, w ile the graming promotes the adhesion of the gelatine layer. Grooves having vertical sides are specially favourable for giving the gelatine a firm hold on the celluloid.

In an improved hydrotype process the printing belt is prepared similarly to collotype, but comprises a perforated backing or foundationwhichacts as an ink or colour reservoir, being fed with a watery or spirituous ink or dye from behind, which therefore passes through the erforations, and through the porous soft gel tine parts of the image, but not through the hardened parts, and is then transferred to the film by pressure. The picture from-the original picture film is printed upon the gelatine layer which is spread over the surface of the belt and by uniting with the gelatine in the slits or holes thereby sucks up the watery ink or colour applied to the back. This front layer is treated as in the ordinary collotype process to produce a printing surface.

To secure the adhesion of the gelatine or other colloid to the band, the latter may be corrugated, grooved, perforated or roughened, and the band "is stamped or cut with numerous small and closely grouped slits or perforations into which the gelatine will penetrate. This allows the ink or colour to be applied to the gelatine layer from the back of the band. The picture from the original picture film is printed upon the gelatine layer and treated as in the ordinary gollotype process to produce a printing surace.

In the preparation of the printing belts, when printing through the screen it is desirable that the screen should be moved slightlyrelatively to the belteither laterally or longitudinally or both after each individual plcture is exposed, so that the indentations or pits'in the printing surface of the printing belt and subsequently the dots or points or lines printed therefrom upon the kinematograplr film will not fall in the same place in the successive pictures, and so, owing to the rapidity of projection and the persistence of vision, such dots or points will not be visible on the enlargement when projected upon a sheet or screen, the pictures appearing as a full tone grainless picture.

The lcz'nematogmph film-The strip or film upon which the pictures are to be printed from the printing belts to produce the finished kinematograph film may be of the 'ordinary celluloid material now employed for kinematograph films or any other transparent film material.

Mechanical printing of Icinenmto'gmplz fiZms.In the mechanical printing of the films from the printing belts herein described any suitable printing ink of a watery or spirituous description or one containing glycerine, and all containin dye or other similar dissolved colours (ot er than particles of pigment) may be employed that is adapted to the particular form of printing belt and the surface of the film upon which th ei rint is to be maged b w lh e rintin may e. one y app yin t e ink to the priiiting belts by any well'kiiown printing method such as. by rollers applying it to the face, or by rollers or damping pads applying it to the back, or by passing the belt through a trough of the watery or spirituous ink or dye.

The printingbelts with perforations along the margins in which registering pinscan operate and the film also similarly perfo; rated afong the margins, are drawn together between rollers or pressing surfaces by 'whichcontact or pressure will be applied picture by picture. Sprocket teeth or claws are fitted to draw the two through the machine in correct register.

What I claim as in invention and desire to protect by Letters atent is l. A porous photo-mechanical printing belt for the production of continuous indefinite lengths of kinematograph positive film pictures, provided with perforations and a series of printing clichs formed on the surface, and having pictures arranged in succession longitudinally thereon, each clich being capable of printing a half-tone image with all the gradatiomof a photograph by r planographic methods; the clich consisting of a large number of broken tone markings, of a spongy character, capable of absorbing an ink, and from whence it is capable of being transferred to the film to be printed by means of applied pressure, and the interspaces between these broken tone markings representing the whites of the picture consisting of non-porous material which cannot absorb the ink; and the gradation of image being formed by making the said printing broken tone markings of Varying size and area so that they are capable of depositing Varying areas of ink, and thus forming a series of printed images of full gradation by theagency of applied ink. and pressure.

2. A porous photo-mechanical printing belt for the production of continuous indefinit-e. lengths of kinematograph positive film pictures, provided with perforations and a series of printing clichs formed on the surface and having pictures arranged in succession longitudinally thereon, each clich being capable of printing a half-tone image with all the gradation of a photograph by planographic methods; the clich consisting of a large number of broken tone markings of a spongy character, through which the ink can percolate from the back of the belt to the front printing surface, and from whence it is capable of being transferred to the film to be printed by means" of applied pressure,=and the ,interspaces between these broken tone markings representing the whites of the picture consisting of non-porous material through which the ink cannot penetrate; and the gradation of image being formed by making the said printing broken tone markings of varying size and area so that they are capable of depositing varying areas of ink, and thus forming a series of printed images of full gradation by the agency of applied ink and pressure.

3. A series of porous perforated photo mechanical printing belts for producing continuous indefinite lengths of kinematograph positive films, as in claim 2, for printing the main part of each image by one printing belt, and intensifying parts of each image, by printing from another: printing belt, the corresponding parts of each image of the series being difierent in ink area for each belt, and requiring the printing from all belts in succession to complete the series I vvaried in relation to the particular part of the picture image upon every printing belt of the series, in order that the grain of the picture may be obliterated. by the successive printings, and thus form a series of fulltone grainless film pictures by aqueous ink applied through the back of the belt and by pressure and superimposed printings.

5. A series of perforated photo-mechanical printing belts for producing continuous indefinite lengths of kinematograph positive prints in multi-colour heliochrome, by means of a large number of broken tone markings of spongy character and of varying size and area as in claim 1, each colour of the composite heliochrome being formed upon a separate belt, which belts are subsequently printed on to the film by superimposed planographic printing, and by aqueous inks applied through the back of the belt, and by pressure, to produce complete heliochrome continuous positive films.

6. A series of perforated photo-mechanical printing belts for producing continuous indefinite lengths of kinematograph positive prints in multi-colour heliochrome, by means of a large number of broken tone markings of spongy character and of varying size and area as in claim 1-, the composite heliochrome being split into a plurality of. printings of each colour, and each being printed from a different belt in which the printing points have their incidence varied in relation to the same particular part of the picture image, in order that the broken tone markings of one printing may be obliterated by the second printing of the same section of the picture, with the object of producing when the remaining colours of'the image series have been similarly split andvap-plied a series of grainless full-tone heliochrome kinematograph positive film pictures, by aqueous inks applied through the back of the belt and pressure and superimposed p-lanographic printings. y

7. A continuous planographic printing belt of indefinite length as in claim 1, having its printing cliches produced by spongy ink is applied to the back of the spongy printing belt to penetrate to the front.

8. A continuous spongy printing belt, as in claim 1 having its surface grooved to promote adhesion of the clichs formed on its face and prevent their tearing off during inking and printing.

9. A continuous planographic printing belt for direct printing on to a continuous kinematograph film, and prepared with spongy planographic images by the improved hydrotype methods as in claim 1, in which the incidence of the screen marking is varied in each succeeding picture of the series therein.

10. A photo-mechanical perforated or notched printing belt, having formed thereon by photo chemical means a series of printing clichs, each composed of a large number of spongy printing points, the gradation of each .image being formed by making the said printing points of varying size and area, to render them capable of depositing varying areas of ink to form pictures, in the form of a continuous longitudinally series upon a continuous indefinite length of kinematograph film, the said inks being of an aqueous character, and applied to the film during printing through the back of the spongy printing belt, substantially as described.

11. A continuous printing belt as in claim 1, having its printing clichs produced by planographic methods, in which some parts are non-porous, corresponding to the whites of thepicture, some parts extremely porous, corresponding to the shadows of the picture, and some parts less porous corresponding to the half-tones of the picture, and formed in a series of markings of varying area, and provided with apertures filled with spongy colloid through which the printing belt is fed With inks or dyes from the back, such inks being fed through the porous portions of the belt from back to front, and transferred from the front to an absorbent film surface by applied pressure.

12. A perforated photo-mechanical continuous printing belt having planographic clichs thereon, formed with holes in its body which are filled With spongy filling that is also continued on to the back and front parts of the belt, to act as an ink feed fountain, by Which aqueous ink containing colour applied to the back of the belt whilst it is moving is gradually fed through the belt to the porous portions of the clichs attached to its face, when used for planographic processes.

In testimony. whereof I have hereunto set my hand in presence of two subscribing witnesses.

JOHN EDWARD THORNTON.

Witnesses:

J. OWDEN OBRIEN, W. J. A; HORSWORTHY. 

